Refrigeration System and Refrigerated Storage

ABSTRACT

The present disclosure provides a refrigeration system and a refrigerated storage including the same, relating to the technical field of refrigeration equipment, and solving the technical problems of a high compressor pressure ratio, a reduced refrigeration coefficient and a high exhaust temperature in a refrigerated storage. The refrigeration system includes at least two sets of refrigerant compression devices, a refrigerant evaporation device and a flow path switching valve set, wherein all the refrigerant compression devices are fluidly connected to the flow path switching valve set; the flow path switching valve set is configured to control the refrigerant compression devices by switching the flow path switching valve set to supply a refrigerant to a refrigerant evaporation in an alternative manner or in series. According to the technical solution provided by the present disclosure, double-temperature high-efficiency refrigeration is achieved, and the energy efficiency of the refrigeration system is improved.

CROSS-REFERENCE TO RELATED APPLICATIONS

The application is the United States national phase of International Application No. PCT/CN2020/098447 filed Jun. 28, 2020, and claims priority to Chinese Patent Application No. 201910897189.1, filed on Sep. 23, 2019, the disclosures of which are hereby incorporated by reference in their entirety.

BACKGROUND Field of the Invention

The present disclosure relates to the technical field of refrigeration equipment, and in particular to a refrigeration system and a refrigerated storage.

Description of Related Art

The refrigerated storage usually comprises a freezing room and a refrigerating room, the temperature of the freezing room is −18° C., and the temperature of the refrigerating room is 0° C. The current practice is to use a low-temperature compressor to refrigerate the freezing room and use a medium-temperature compressor to refrigerate the refrigerating room. With the reduction of the evaporation temperature, the pressure ratio increases. When at a high pressure ratio, the low-temperature compressor has the problems of reduced volume efficiency, reduced refrigeration coefficient and high exhaust temperature.

BRIEF SUMMARY OF THE INVENTION

The present disclosure is to provide a refrigeration system and a refrigerated storage, so as to improve the phenomena of high compressor pressure ratio, reduced refrigeration coefficient and high exhaust temperature in the refrigerated storage in related art.

Some embodiments of the present disclosure provide a refrigeration system, including: at least two sets of refrigerant compression devices, wherein each of the refrigerant compression devices is configured to compress a refrigerant; a refrigerant evaporation device; and a flow path switching valve set, wherein all the refrigerant compression devices are fluidly connected to the flow path switching valve set, the flow path switching valve set is configured to control the refrigerant compression devices by switching the flow path switching valve set to supply a refrigerant to the refrigerant evaporation device in an alternative manner or in series.

In some embodiments, each set of refrigerant compressing device has different compression ratios.

In some embodiments, when all the refrigerant compression devices supply refrigerants in series, the compression ratio of the refrigerant compressing device located downstream is greater than the compression ratio of the refrigerant compressing device located upstream.

In some embodiments, the refrigeration system further includes: a cold supply switching valve set fluidly connected to the flow path switching valve set; and at least two refrigerant evaporation devices, wherein the cold supply switching valve set is configured to control the refrigerant by the cold supply switching valve set to flow towards at least one refrigerant evaporation device.

In some embodiments, there are two sets of refrigerant compression devices, namely a first cold supply assembly and a second cold supply assembly; an outlet pipeline of the first cold supply assembly is fluidly connected to the flow path switching valve set, and an inlet pipeline and an outlet pipeline of the second cold supply assembly are both fluidly connected to the flow path switching valve set to form a circulation loop; the cold supply switching valve set includes a first supply pipeline and a second supply pipe; one end of the first supply pipeline is fluidly connected to the flow path switching valve set and the other end of the first supply pipeline flows back to the first cold supply assembly after passing through an evaporator of one refrigerant evaporation device; and one end of the second supply pipeline is connected to the cold supply switching valve set and the other end of the second supply pipeline is fluidly connected to the flow path switching valve set by an evaporator of the other refrigerant evaporation device.

In some embodiments, the first cold supply assembly includes a first compressor, and the second cold supply assembly includes a second compressor and a condenser.

In some embodiments, the flow path switching valve set includes a cooler and a first throttle valve; an outlet pipeline of the first compressor communicates with the cooler; an inlet pipeline and an outlet pipeline of the second compressor both communicate with the cooler; and the first throttle valve is arranged on a pipeline between the condenser and the cooler.

In some embodiments, the outlet pipeline of the first compressor extends below a liquid level in the cooler; two ends of the circulation loop are both connected to a position above the liquid level in the cooler; two ends of the circulation loop are respectively connected to two positions on the cooler located above the liquid level in the cooler; and the second supply pipeline and the first supply pipeline are respectively connected to two positions on the cooler located below the liquid level in the cooler.

In some embodiments, the cold supply switching valve set further includes a second throttle valve and a pump; the second throttle valve is arranged on the first supply pipeline; and the pump is arranged on the second supply pipeline.

In some embodiments, the refrigerant compressing device includes: a compressor, provided with a first fluid outlet and a first fluid inlet; a cooler, provided with a second fluid inlet, a second fluid outlet, a third fluid inlet and a fourth fluid outlet, wherein the first fluid outlet communicates with the second fluid inlet, and the second fluid outlet communicates with the first fluid inlet; and a second compressor, provided with a fourth fluid inlet and a fourth fluid outlet, wherein the fourth fluid outlet communicates with the fourth fluid inlet, and the fourth fluid outlet communicates with the third fluid inlet.

In some embodiments, the flow path switching valve set includes: a first throttle valve, arranged on a pipeline between the fourth fluid outlet and the third fluid inlet; and a second throttle valve, arranged on a pipeline between the second fluid outlet and the first fluid inlet.

In some embodiments, the refrigerant compressing device further includes: a condenser, arranged between the first throttle valve and the second compressor.

In some embodiments, the refrigerant evaporation device includes: a first evaporator, provided with a liquid inlet and a gas outlet, wherein the liquid inlet communicates with the second fluid outlet, and the gas outlet communicates with a fifth fluid inlet of the cooler; and a second evaporator, arranged between the second throttle valve and the first fluid inlet.

Some other embodiments of the present disclosure provide a refrigerated storage, including: a freezing storage; a refrigeration storage; and the refrigeration system provided by any technical solution of the present disclosure, wherein the refrigeration system is connected to the freezing storage and the refrigeration storage.

In some embodiments, the refrigerated storage has three refrigeration modes, namely, a refrigeration mode for the freezing storage, a dual-refrigeration mode for both the freezing storage and the refrigeration storage, and a refrigeration mode for the refrigeration storage.

The refrigeration system provided by the present disclosure includes at least two sets of refrigerant compression devices and a flow path switching valve set, wherein the flow path switching valve set can control all the refrigerant compression devices to supply refrigerants for the refrigerant evaporation device in an alternative manner or in series, two compressors form one set of refrigeration system to supply cold for the freezing room and the refrigerating room at the same time, and the first compressor is compressed to an intermediate pressure (the pressure of the refrigerating room); with the reduction of the pressure ratio of each stage, the volume efficiency of the compressor can be improved, so that the energy efficiency of the refrigeration system can be improved; the second low-temperature compressor is started according to different storage temperatures, so the problem of low energy efficiency of the low-temperature refrigerated storage is solved; and the first compressor and the second compressor are connected in series, a cooler is increased in the middle, and the corresponding refrigerant compressing device is started according to different use conditions, so that double-temperature high-efficiency refrigeration is realized, and the energy efficiency of the refrigeration system is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the technical solutions in the embodiments of the present disclosure or related art more clearly, the following briefly describes the accompanying drawings required for describing the embodiments or the related art. Apparently, the accompanying drawings in the following description show merely some embodiments of the present disclosure, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a refrigeration system according to an embodiment of the present disclosure.

FIG. 2 is a schematic diagram of a medium flow direction when a refrigeration system provided by some embodiments of the present disclosure is in a refrigeration mode for the freezing storage.

FIG. 3 is a schematic diagram of a medium flow direction when a refrigeration system provided by some embodiments of the present disclosure is in a dual-refrigeration mode for both of the freezing storage and the refrigeration storage.

FIG. 4 is a schematic diagram of a medium flow direction when a refrigeration system provided by some embodiments of the present disclosure is in a refrigeration mode for the refrigeration storage.

In the drawings: 1. First compressor; 2. Second compressor; 3. Cooler; 4. Condenser; 5. First throttle valve; 6. Pump; 7. Second throttle valve; 8. Circulation loop; 9. First supply pipeline; 10. Second supply pipeline; 100. First evaporator; 200. Second evaporator; 30. Refrigerant compressing device; 40. Flow path switching valve set; 50. Cold supply switching valve set; 60. Refrigerant evaporation device; 301. First cold supply assembly; 302. Second cold supply assembly.

DETAILED DESCRIPTION OF THE INVENTION

Some embodiments of the present disclosure provide a refrigeration system, including a flow path switching valve set 40 and at least two sets of refrigerant compression devices 30, wherein all the refrigerant compression devices 30 are fluidly connected to the flow path switching valve set 40 through fluid. All the refrigerant compression devices 30 are controlled through the flow path switching valve set 40 to supply refrigerants for the refrigerant evaporation device in an alternative manner or in series. That is, the flow path switching valve set 40 controls whether each refrigerant compressing device 30 is in the circulation loop by controlling the communicating and disconnected states of each valve, so that at least one of the refrigerant compression devices 30 communicates with the circulation loop, and the refrigerant compressing device 30 in the communicating state provides a refrigerant for the refrigerant evaporation device. The flow path switching valve set 40 may also connect part or all of the refrigerant compression devices 30 in series, so as to provide the required refrigerant for the refrigerant evaporation device. The series connection means that the refrigerant sequentially passes through each refrigerant compressing device 30.

In some embodiments, different refrigerant compression devices 30 have different compression ratios.

In some embodiments, when all the refrigerant compression devices 30 supply the refrigerant in series, in a medium flowing direction, the compression ratio of the refrigerant compressing device 30 located on a rear side is greater than the compression ratio of the refrigerant compressing device 30 located on a front side.

In some embodiments, the refrigeration system further includes a cold supply switching valve set 50 fluidly connected to the flow path switching valve set 40. There are at least two refrigerant evaporation devices, and the refrigerant can be controlled by the cold supply switching valve set 50 to flow towards any one of part or all of the refrigerant evaporation devices.

As shown in FIG. 1, in one embodiment of the present disclosure, there are two sets of refrigerant compression devices 30, namely a first cold supply assembly 301 and a second cold supply assembly 302; and a medium temperature provided by the first cold supply assembly 301 is less than a medium temperature provided by the second cold supply assembly 302. An outlet pipeline of the first cold supply assembly 301 is fluidly connected to the flow path switching valve set 40, and an inlet pipeline and an outlet pipeline of the second cold supply assembly 302 are both connected to the flow path switching valve set 40 to form a circulation loop 8. The cold supply switching valve set 50 includes a first supply pipeline 9 and a second supply pipeline 10. One end of the first supply pipeline 9 is connected to the flow path switching valve set 40 and the other end of the first supply pipeline 9 flows back to the first cold supply assembly 301 after passing through an evaporator of one refrigerant evaporation device; and one end of the second supply pipeline 10 is fluidly connected to the flow path switching valve set 40 and the other end of the second supply pipeline 10 is fluidly connected to the flow path switching valve set 40 by an evaporator of other one refrigerant evaporation device.

Specifically, the first cold supply assembly 301 includes a first compressor 1, and the second cold supply assembly 302 includes a second compressor 2 and a condenser 4. The second compressor 2 and the condenser 4 are both connected through a pipeline.

The flow path switching valve set 40 includes a cooler 3 and a first throttle valve 5, an outlet pipeline of the first compressor 1 communicates with the cooler 3, an inlet pipeline and an outlet pipeline of the second compressor 2 both communicate with the cooler 3, and the first throttle valve 5 is arranged on a pipeline between the condenser 4 and the cooler 3.

The outlet pipeline of the first compressor 2 extends below a liquid level in the cooler 3, and two ends of the circulation loop 8 are respectively connected to two positions on the cooler 3 located above the liquid level in the cooler 3; and the second supply pipeline 301 and the first supply pipeline 9 are respectively connected to two positions on the cooler 3 located below the liquid level in the cooler 3. The cooler 3 is a flash evaporator, which is a product in related art and purchased from the external market.

The flow path switching valve set 40 further includes a second throttle valve 7 and a pump 6, wherein the second throttle valve 7 is arranged on the first supply pipeline 9; and the pump 6 is arranged on the second supply pipeline 10.

In some embodiments, the refrigerant compressing device 30 includes a first compressor 1, a second compressor 2 and a cooler 3. The compressor 1 is provided with a first fluid outlet 101 and a first fluid inlet 102. The cooler 3 is provided with a second fluid inlet 31, a second fluid outlet 32, a third fluid inlet 33 and a fourth fluid outlet 34. The first fluid outlet 101 communicates with the second fluid inlet 31, and the second fluid outlet 32 communicates with the first fluid inlet 102. The second compressor 2 is provided with a fourth fluid inlet 21 and a fourth fluid outlet 22; and the fourth fluid outlet 34 communicates with the fourth fluid inlet 21, and the fourth fluid outlet 22 communicates with the third fluid inlet 33. By controlling the valve position of the flow path switching valve set 40, the first compressor 1 and the second compressor 2 are either or both located in the circulation loop. Specifically, in the refrigeration mode for the refrigeration storage, only the second compressor 2 works. In the dual-refrigeration mode for both of the refrigeration storage and the freezing storage, the first compressor 1 and the second compressor 2 work at the same time; moreover, the refrigerant obtained after secondary compression of the first compressor 1 and the second compressor 2 is provided to the first evaporator 100 in the refrigeration storage and the second evaporator 200 in the freezing storage at the same time. In the refrigeration mode for the refrigeration storage, the first compressor 1 and the second compressor 2 work at the same time; moreover, the refrigerant obtained after secondary compression of the first compressor 1 and the second compressor 2 is only provided to the second evaporator 200 in the freezing storage.

Referring to FIG. 1, in some embodiments, the flow path switching valve set 40 includes a first throttle valve 5 and a second throttle valve 7. The first throttle valve 5 is arranged on a pipeline between the fourth fluid outlet 22 and the third fluid inlet 33. The second throttle valve 7 is arranged on a pipeline between the second fluid outlet 32 and the first fluid inlet 102. By controlling the conduction status of the first throttle valve 5 and the second throttle valve 7, it is simple and convenient to control whether the first compressor 1 and the second compressor 2 are in the circulation loop.

Referring to FIG. 1, in some embodiments, the refrigerant compressing device 30 further includes a condenser 4, and the condenser 4 is arranged between the first throttle valve 5 and the second compressor 2.

Referring to FIG. 1, in some embodiments, the refrigerant evaporation device 60 includes a first evaporator 100 and a second evaporator 200. The first evaporator 100 is provided with a liquid inlet 100 a and a gas outlet 100 b, the liquid inlet 100 a communicates with the second fluid outlet 32, and the gas outlet 100 b communicates with a fifth fluid inlet 35 of the cooler 3. The second evaporator 200 is arranged between the second throttle valve 7 and the first fluid inlet 102.

Some embodiments of the present disclosure provide a refrigerated storage, including a freezing storage, a refrigeration storage and a refrigeration system. The refrigeration system is connected to the freezing storage and the refrigeration storage. The first evaporator 100 is arranged in the refrigeration storage, and the second evaporator 200 is arranged in the freezing storage. The first supply pipeline 9 is connected to the second evaporator 200, and the second supply pipeline 10 is connected to the first evaporator 100.

As shown in FIG. 2 to FIG. 4, the refrigerated storage has three refrigeration modes, namely a refrigeration mode for the freezing storage, a dual-refrigeration mode for both of the freezing storage and the refrigeration storage, and a refrigeration mode for the refrigeration storage. In the refrigeration mode for the freezing storage, only the freezing storage is refrigerated, and the refrigeration storage is not refrigerated. In the dual-refrigeration mode for both of the freezing storage and the refrigeration storage, the freezing storage and the refrigeration storage are refrigerated. In the refrigeration mode for the refrigeration storage, only the refrigeration storage is refrigerated, and the freezing storage is not refrigerated.

The refrigeration system provided by some embodiments of the present disclosure adopts two compressors, that is, a first compressor 1 and a second compressor 2 are connected in series to form a bipolar system. The second compressor 2 may operate independently, the second compressor 2 and the first compressor 1 may operate at the same time, the first compressor 1 and the second compressor 2 are connected in series, and the first compressor 1 is compressed to an intermediate pressure (the pressure of the refrigerating room); with the reduction of the pressure ratio of each stage, the volume efficiency of the compressor can be improved, so that the energy efficiency of the refrigeration system can be improved; the first compressor 1 and the second compressor 2 are started according to different storage temperatures to solve the problem of low energy efficiency of the low-temperature refrigerated storage; and the first compressor 1 and the second compressor 2 are connected in series, the cooler 3 is increased in the middle, and the corresponding compressing device is started according to different use conditions, so that double-temperature high-efficiency refrigeration is realized, and the energy efficiency of the refrigeration system is improved.

The following examples are given for detailed description.

Firstly, the refrigeration mode for the freezing storage is introduced. As shown in FIG. 2, in this mode, the freezing storage needs refrigeration, and the refrigeration storage does not need refrigeration. As shown in Table 1, the on/off status of each part of the refrigeration system is as follows: the first compressor 1, the second compressor 2, the first throttle valve 5 and the second throttle valve 7 are turned on, and the pump 6 is turned off; and the first compressor 1 is compressed to an intermediate pressure and discharges the compressed gas to the cooler 3 for cooling. The second compressor 2 absorbs the saturated gas in the cooler 3 and discharges the compressed gas to the condenser 4. A gas-liquid mixture formed after primary throttling of the first throttle valve 5 enters the cooler 3, gas is separated in the cooler 3, the separated saturated gas is sucked by the second compressor 2 again for compression, and saturated liquid in the cooler 3 is discharged to the second evaporator 200 through secondary throttling of the second throttle valve 7.

TABLE 1 First Second First throttle Second Pump throttle compressor 1 valve 5 compressor 2 6 valve 7 On On On Off On

Secondly, the dual-refrigeration mode for both of the freezing storage and the refrigeration storage is introduced. As shown in FIG. 3, in this mode, the freezing storage and the refrigeration storage both need refrigeration. At this time, as shown in Table 2, the on/off status of each part of the refrigeration system is as follows: the first compressor 1, the second compressor 2, the first throttle valve 5, the second throttle valve 7 and the pump 6 are turned on. The first compressor 1 compresses a medium to an intermediate pressure and discharges gas to the cooler 3 for cooling. The pump 6 is turned on to supply liquid for the first evaporator 100, and the liquid absorbs heat of the refrigeration storage and returns to the cooler 3 for gas and liquid separation. Low-pressure exhaust and gas compressed exhaust separated in the cooler 3 after evaporation of the refrigeration storage are absorbed by the second compressor 2 to the condenser 4 and then flow to the cooler 3 after the primary throttling of the first throttle valve 5, and saturated liquid is discharged to the second evaporator 200 through the secondary throttling of the second throttle valve 7.

TABLE 2 First Second First throttle Second throttle compressor 1 valve 5 compressor 2 Pump 6 valve 7 On On On On On

Finally, the refrigeration mode for the refrigeration storage is introduced. As shown in FIG. 4, in this mode, only the refrigeration storage needs refrigeration, and the freezing storage does not need refrigeration. As shown Table 3, the on/off status of each part of the refrigeration system is as follows: the second compressor 2, the first throttle valve 5 and the pump 6 are turned on. The first compressor 1 and the second throttle valve 7 are both turned off; the second compressor 2 compresses the exhaust to the condenser 4, the pump 6 is turned on to supply liquid for the first evaporator 100, and the liquid absorbs the heat of the refrigeration storage to return to the cooler 3 for gas and liquid separation; and after the second compressor 2 absorbs gas separated in the cooler 3 after evaporation of the refrigeration storage for compression to perform the next refrigeration circulation.

TABLE 3 First Second First throttle Second [0001] throttle compressor 1 valve 5 compressor 2 Pump 6 valve 7 Off On On On Off

In the present disclosure, unless otherwise clearly specified and limited, the terms “mounting”, “interconnection”, “connection” and “fixation” etc. are intended to be understood in a broad sense. For example, the “connection” may be a fixed connection, removable connection or integral connection; may be a mechanical connection or electrical connection; may be a direct connection or indirect connection using a medium; and may be a communication or interaction between two elements, unless otherwise explicitly limited. For those of ordinary skill in the art, specific meanings of the foregoing terms in the present disclosure may be understood according to specific circumstances.

In the description of the present disclosure, it should be understood that an azimuth or position relationship indicated by terms “center”, “longitudinal”, “transverse”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer” and the like is an azimuth or position relationship based on the accompanying draws, which is only for facilitating description of the present disclosure and simplifying description, but does not indicate or imply that the referred device or component must have a specific azimuth and perform construction and operation in the specific azimuth; therefore, it cannot be interpreted as a limitation to the protection scope of the present disclosure.

Finally, it should be noted that the above embodiments are merely intended to illustrate the technical solutions of the present disclosure and are not to limit them. Although the present disclosure has been illustrated in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that modification can be made on the specific embodiments of the present disclosure and equivalent replacement can be made on part of the technical features; and the modification and the equivalent replacement should be covered within the protection scope of the technical solutions claimed by the present disclosure without departing from the spirit of the technical solutions of the present disclosure. 

1. A refrigeration system, comprising: at least two sets of refrigerant compression devices, wherein each of the refrigerant compression devices is configured to compress a refrigerant; a refrigerant evaporation device; and a flow path switching valve set, wherein all the refrigerant compression devices are fluidly connected to the flow path switching valve set, the flow path switching valve set is configured to cause the refrigerant compression devices by means of switching the flow path switching valve set to supply a refrigerant to the refrigerant evaporation device in an alternative manner or in series.
 2. The refrigeration system according to claim 1, wherein each set of refrigerant compressing devices has different compression ratios.
 3. The refrigeration system according to claim 2, wherein when all the refrigerant compression devices supply refrigerants in series, the compression ratio of the refrigerant compressing device located downstream is greater than the compression ratio of the refrigerant compressing device located upstream.
 4. The refrigeration system according to claim 1, further comprising: a cold supply switching valve set fluidly connected to the flow path switching valve set; and at least two refrigerant evaporation devices, wherein the cold supply switching valve set is configured to cause the refrigerant by the cold supply switching valve set to flow towards at least one refrigerant evaporation device.
 5. The refrigeration system according to claim 4, wherein there are two sets of refrigerant compression devices, namely a first cold supply assembly and a second cold supply assembly; an outlet pipeline of the first cold supply assembly is fluidly connected to the flow path switching valve set, and an inlet pipeline and an outlet pipeline of the second cold supply assembly are both fluidly connected to the flow path switching valve set to form a circulation loop; the cold supply switching valve set comprises a first supply pipeline and a second supply pipe; one end of the first supply pipeline is fluidly connected to the flow path switching valve set and the other end of the first supply pipeline flows back to the first cold supply assembly after passing through an evaporator of one refrigerant evaporation device; and one end of the second supply pipeline is fluidly connected to the cold supply switching valve set and the other end of the second supply pipeline is fluidly connected to the flow path switching valve set by an evaporator of the other refrigerant evaporation device.
 6. The refrigeration system according to claim 5, wherein the first cold supply assembly comprises a first compressor, and the second cold supply assembly comprises a second compressor and a condenser.
 7. The refrigeration system according to claim
 6. wherein the flow path switching valve set comprises a cooler and a first throttle valve; an outlet pipeline of the first compressor communicates with the cooler; an inlet pipeline and an outlet pipeline of the second compressor both communicate with the cooler; and the first throttle valve is arranged on a pipeline between the condenser and the cooler.
 8. The refrigeration system according to claim 7, wherein the outlet pipeline of the first compressor extends below a liquid level in the cooler; two ends of the circulation loop are respectively connected to two positions on the cooler located above the liquid level in the cooler; and the second supply pipeline and the first supply pipeline are respectively connected to two positions on the cooler located below the liquid level in the cooler.
 9. The refrigeration system according to claim 7, wherein the cold supply switching valve set further comprises a second throttle valve and a pump; the second throttle valve is arranged on the first supply pipeline; and the pump is arranged on the second supply pipeline.
 10. The refrigeration system according to claim 1, wherein the refrigerant compressing device comprises: a compressor, comprising a first fluid outlet and a first fluid inlet; a cooler, comprising a second fluid inlet, a second fluid outlet, a third fluid inlet and a fourth fluid outlet, the first fluid outlet communicating with the second fluid inlet, and the second fluid outlet communicating with the first fluid inlet; and a second compressor, comprising a fourth fluid inlet and a fourth fluid outlet, the fourth fluid outlet communicating with the fourth fluid inlet, and the fourth fluid outlet communicating with the third fluid inlet.
 11. The refrigeration system according to claim 10, wherein the fluid path switching valve set comprises: a first throttle valve, arranged on a pipeline between the fourth fluid outlet and the third fluid inlet; and a second throttle valve, arranged on a pipeline between the second fluid outlet and the first fluid inlet.
 12. The refrigeration system according to claim 11, wherein the refrigerant compressing device further comprises: a condenser, arranged between the first throttle valve and the second compressor.
 13. The refrigeration system according to claim 11, wherein the refrigerant evaporation device comprises: a first evaporator, comprising a liquid inlet and a gas outlet, the liquid inlet communicating with the second fluid outlet, and the gas outlet communicating with a fifth fluid inlet of the cooler; and a second evaporator, arranged between the second throttle valve and the first fluid inlet.
 14. A refrigerated storage, comprising: a freezing storage; a refrigeration storage; and a refrigeration system comprising: at least two sets of refrigerant compression devices, wherein each of the refrigerant compression devices is configured to compress a refrigerant; a refrigerant evaporation device; and a flow path switching valve set, wherein all the refrigerant compression devices are fluidly connected to the flow path switching valve set, the flow path switching valve set is configured to cause the refrigerant compression devices by means of switching the flow path switching valve set to supply a refrigerant to the refrigerant to the refrigerant evaporation device in an alternative manner or in series; wherein the refrigeration system is connected to the freezing storage and the refrigeration storage.
 15. The refrigerated storage according to claim 14, wherein the refrigerated storage has three refrigeration modes, namely, a refrigeration mode for the freezing storage, a dual-refrigeration mode for both of the freezing storage and the refrigeration storage, and a refrigeration mode for the refrigeration storage. 